
SN54HCT645, SN74HCT645
OCTAL BUS TRANSCEIVERS
WITH 3STATE OUTPUTS
SCLS019D MARCH 1984 REVISED AUGUST 2003
3
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
recommended operating conditions (see Note 3)
SN54HCT645
SN74HCT645
UNIT
MIN
NOM
MAX
MIN
NOM
MAX
UNIT
VCC
Supply voltage
4.5
5
5.5
4.5
5
5.5
V
VIH
High-level input voltage
VCC = 4.5 V to 5.5 V
2
V
VIL
Low-level input voltage
VCC = 4.5 V to 5.5 V
0.8
V
VI
Input voltage
0
VCC
0
VCC
V
VO
Output voltage
0
VCC
0
VCC
V
t/v
Input transition rise/fall time
500
ns
TA
Operating free-air temperature
55
125
40
85
°C
NOTE 3: All unused inputs of the device must be held at VCC or GND to ensure proper device operation. Refer to the TI application report,
Implications of Slow or Floating CMOS Inputs, literature number SCBA004.
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
VCC
TA = 25°C
SN54HCT645
SN74HCT645
UNIT
PARAMETER
TEST CONDITIONS
VCC
MIN
TYP
MAX
MIN
MAX
MIN
MAX
UNIT
VOH
VI = VIH or VIL
IOH = 20 A
4.5 V
4.4
4.499
4.4
V
VOH
VI = VIH or VIL
IOH = 6 mA
4.5 V
3.98
4.3
3.7
3.84
V
VOL
VI = VIH or VIL
IOL = 20 A
4.5 V
0.001
0.1
V
VOL
VI = VIH or VIL
IOL = 6 mA
4.5 V
0.17
0.26
0.4
0.33
V
II
DIR or OE
VI = VCC or 0
5.5 V
±0.1
±100
±1000
nA
IOZ
A or B
VO = VCC or 0
5.5 V
±0.01
±0.5
±10
±5
A
ICC
VI = VCC or 0,
IO = 0
5.5 V
8
160
80
A
ICC
One input at 0.5 V or 2.4 V,
Other inputs at 0 or VCC
5.5 V
1.4
2.4
3
2.9
mA
Ci
DIR or OE
4.5 V
to 5.5 V
3
10
pF
This is the increase in supply current for each input that is at one of the specified TTL voltage levels rather than 0 V or VCC.
switching characteristics over recommended operating free-air temperature range, CL = 50 pF
(unless otherwise noted) (see Figure 1)
PARAMETER
FROM
TO
VCC
TA = 25°C
SN54HCT645
SN74HCT645
UNIT
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
VCC
MIN
TYP
MAX
MIN
MAX
MIN
MAX
UNIT
tpd
A or B
B or A
4.5 V
16
22
33
28
ns
tpd
A or B
B or A
5.5 V
14
20
30
25
ns
ten
OE
A or B
4.5 V
25
46
69
58
ns
ten
OE
A or B
5.5 V
22
41
62
52
ns
tdis
OE
A or B
4.5 V
26
40
60
50
ns
tdis
OE
A or B
5.5 V
23
36
54
45
ns
tt
A or B
4.5 V
9
12
18
15
ns
tt
A or B
5.5 V
8
11
16
14
ns
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.